This invention relates generally to single-ply roofing systems.
After its introduction, single-ply roofing systems have attracted growing interest and use in the roofing industry. Single-ply roofing systems have many advantages over the well known and used built-up type roof systems. Specifically, built-up roof members were very highly labor intensive in installation and required large capital investment in equipment necessary for installation. Further, built up roof members were very susceptible to the elements. They often split due to expansion and contraction, blister due to moisture penetration between the plies, and rot from standing water on them.
Single-ply roofing systems are easier and faster to install and do not require expensive installation equipment. Further, single-ply roofing systems overcame many of the other problems experienced in built-up roof systems. In single-ply roofing systems, the use of sheets made of ethelene-propelene-diene-monomer (EPDM) has outpaced other material such as sheets of poly vinyl chloride (PVC), neoprene, and poly isobutelene (PIB), and thus EPDM, in general has had greater acceptance by building owners, architects, and roofing contractors. Specifically, EPDM membranes have excellent resistance to ultra-violet rays and will withstand thousands of hours of exposure to sunlight without cracking or deteriorating. Its service temperature range is from -50.degree. F. to 240.degree. F. EPDM membranes have excellent resistance to corrosive chemicals, mineral acids, and vegetable oils. Its extreme elongation factors, high tensile strength, and general compatibility with other materials makes it applicable for most roofing applications both on new construction and reroofing projects. Roofing systems utilizing EPDM membranes are easy for the owner to maintain, modify or even remove and reuse in cases where the building is to be demolished or increased in height.
However, single-ply roofing has had its own problems, some relating to attaching the sheets to the roof surface and to flashings. Prior to the present invention, an adhesive was used, but this has several known shortcomings. First, the adhesive will not keep out water by itself. Therefore, a water seal such as caulk must be placed at all joints where the adhesive is exposed. Second, the adhesive must be allowed to flash off for a period of time depending upon the temperature, a very time consuming procedure. Further, because of its temperature dependence, the adhesive can only be applied during certain seasons and atmospheric conditions. Third, EPDM is often manufactured with talc powder located on both sides. This talc powder as well as any other dirt or residue on the EPDM surface must be hand removed using a solvent, for example, toluene or xylene, and a rag prior to the application of the adhesive to the EPDM sheet. Again, this is very time consuming. Therefore, many extra steps are required in using the adhesive. Fourth, because the adhesive contains solvents which are corrosive to certain types of insulation used on roof decks, elaborate precautions must be taken to avoid contact of adhesive to these types of insulation, for example such as the type set forth in U.S. Pat. No. 4,162,597. Fifth, the adhesive must be hand applied with rollers, brushes or other hand implements to both surfaces to be attached together. This is also very time consuming. Sixth, the adhesive is extremely flammable and explosive. Also, the fumes of the adhesive is a liquid state are harmful to human health. Thus, precautions are necessary when utilizing adhesive for health and safety reasons which are not necessary for a roof system utilizing the teachings of the present invention. Many other disadvantages of the use of adhesive in the prior art are known and will also be obvious once the teachings of the present invention are known.
The present invention then relates to improvements in single-ply roofing systems, of either the ballasted type or unballasted type, such as mechanically fastened or fully adhered, to name just two.
Thus, it is an object of the present invention to provide an improved and novel single-ply roofing system.
It is further an object of the present invention to provide such single-ply roofing system having novel methods for attaching the roof sheet to roof edges which are water resistant.
It is further an object of the present invention to provide such single-ply roofing system having novel methods for attaching the roof sheet to the roof surface.
It is further an object of the present invention to provide such single-ply roofing system having novel methods of attaching the roof sheet to the roof without the use of adhesive.
It is further an object of the present invention to provide such single-ply roofing system utilizing sealing members which will have an increasing bonding strength with the roof sheet over a period of time.
It is further an object of the present invention to provide such single-ply roofing system which is prefabricated off the job site for rapid and simple installation on the job site.
It is further an object of the present invention to provide a novel roofing sealing member.
It is further an object of the present invention to provide such a novel roofing sealing member including added protection against moisture penetration when the sealing members overlap.
These and further objects and advantages of the present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.